1. Field of the Invention
The present invention relates to a photographing apparatus such as a digital camera, and in particular to a photographing apparatus provided with an object detection function.
2. Description of the Related Art
Among photographing apparatuses such as digital cameras and digital video cameras in recent years, those provided with an object detection function to detect an object, such as a face, from a photographed image have been proposed. For example, a photographing method for use with such photographing apparatuses, in which exposure and focusing operations for photographing a subject are automatically controlled based on a result of object detection achieved by the object detection function, and a photographing apparatus that determines the orientation of a face detected by the face detection function, and records the subject according to the result of the determination to reliably photograph a front-oriented face (Japanese Unexamined Patent Publication No. 2001-051338) have been proposed.
Further, an authentication apparatus that automatically detects the orientation of a face contained in photographed images, and selects one of the images containing a front-oriented face to compare the front-oriented face with each of front-oriented faces contained in images for checking, thereby authenticating a certain individual (Japanese Unexamined Patent Publication No. 2002-288670).
Further, the face detection function may have a problem such that face detection cannot reliably be carried out depending on a photographing environment during face detection, resulting in poor detection accuracy. To address this problem, a photographing apparatus disclosed in Japanese Unexamined Patent Publication No. 2006-229367 carries out the face detection only while a photographing mode which is assumed to be used for photographing a scene containing a person is set.
When the face detection function is used with a detection range that is widened to detect faces in various different conditions, such as faces with various orientations and/or sizes, the faces in various different conditions can be detected; however, a rate of erroneous detection may be increased. In addition, the face detection with the widened detection range takes a longer time, and this may result in poor followability. The “detection range” used herein means not only a spatial detection range (positions), but also variation of the conditions of objects to be detected (size, orientation, inclination, and the like).
When a photographing operation is carried out using the face detection function, demands of the user may vary depending on the scene to be photographed, such that putting a priority on the speed of the face detection or on the rate of the face detection. In this case, it is difficult for the above described conventional face detection function to set or change the face detection conditions.